CO.sub.2 laser and YAG lasers are mainly in the form of industrial lasers. In addition to those lasers, Ar lasers are used as medical power lasers. Laser fibers are used for transmitting various sorts of laser light, and laser fibers made of silicon glass are employed generally for lasers, except for CO.sub.2 lasers which may melt glass. By using laser fibers, it is possible to transmit laser light effectively over long distances, for example, about 100 m. In use, separate laser fibers are often connected to each other for the purpose of branching or distributing laser light from one power laser to a plurality of places where the laser light is to be used, or for other purposes.
In the construction of conventional laser fiber connectors, scatter reflections of laser light at rates of from several to several tens % have occured at connecting portions, thereby causing accidents due to resultant heat, such as fires, or the like. A power laser having a high output on the order of from seVeral to several hundreds watts, results in a high possibility of accidents such as a fire, or the like, caused by heat due to the scatter reflections of laser light at the connecting portions of the laser fibers, if the rate of the scatter reflections is large. In order to solve this problem, conventionally, laser fibers to be connected to each other are brought into close contact with each other and then connected through fusion or by using a bonding agent. In this case, however, if the laser fibers to be connected are fixedly connected to each other, there is the disadvantage that the whole of the fibers must be replaced when an end of any one of the laser fibers is made unusable by damage.
In the case where foreign matter or filth adheres to the emission side tip end of the laser fiber in operations of mechanical processing or medical treatment, and if laser irradiation is performed with the foreign matter or filth adhered, avoidable damage due to heat may be caused to the tip end of the laser fiber, and the tip end is apt to be damaged by mechanical impact. In this case, the replacement of the whole of the laser fibers causes no problem if the laser fibers are short, for example, on the order of several meters. However, a large loss results in the case where the laser fibers are on the order of several tens of meters, in view of both workability and economy. Therefore, there is needed a connecting structure for laser fibers which has no connecting loss and no possibility of occurrence of heat problems.
It is, therefore, a primary object of the present invention to provide a conventional power laser apparatus with a connecting structure for laser fibers which results in reduced connecting loss, and wherein, even if scatter reflections result in the generation of heat, the heat may be dissipated effectively.